I think it's at least somewhat likely that this was staged to get even more publicity for the product.

The reason I say this is static web content is easy to scale; there should be no reason for all of target.com to go down.

I don't think you know how large ecommerce websites work. Pricing, availability, listing pages are all generated dynamically. "Static web content" doesn't even get close to describing how an ecom page gets served with that many variables. You can't simply create a version for every permutation of visitor and cache it.